API

The onFact API allows you to automatically call functions within onFact from an external program. For example, an external program can securely retrieve customer lists, create new customers, or generate documents.

An “API” is a technical interface that can be accessed from an external program. Accessing the API requires technical knowledge, and you will need to program new functions within the external program to interact with this API.

The “API” follows the classic REST architecture. Detailed information about each API function can be found at the following link: API Reference

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Authentication

API Key Authentication

The simplest way to authenticate the integration is via an API key. This method is intended for integrations developed specifically for a single company by that company. If you are developing an integration with onFact for multiple users, you should use “oAuth 2.0 authentication.”

For authentication via API key, you must add two headers to each request: the X-SESSION-KEY and the X-COMPANY-UUID headers. These can be found in onFact via the “Personal Settings” menu in the top-right corner.

Retrieving Invoices

GET https://api5.onfact.be/v1/invoices.json Retrieve a list of invoices

Headers

Name	Type	Description
X-COMPANY-UUID	string	UUID van het bedrijf
X-SESSION-KEY	string	API Key

200 {...}

URL Extensions

The REST API describes the resource endpoints without an extension; this must still be added to the URL. The extension determines the format in which the resources are displayed. In almost all cases, you will need to add the .json extension to the URL. For documents, you can also use the .pdf, .html, or .xml extensions.

To retrieve an invoice in JSON format, you will need to use the following request:

Retrieve invoice details

GET https://api5.onfact.be/v1/invoices/:id.json

Retrieve the information from 1 invoice

Path Parameters

Name	Type	Description
id	string	Factuur ID

Headers

Name	Type	Description
X-SESSION-KEY	string	API Key
X-COMPANY-UUID	string	UUID Van het bedrijf

200​

Special Functions

To simplify API usage, several special functions are built in when creating documents. For example, you can specify an action immediately upon creating a document so that onFact links the newly created document to a customer record or creates a new customer record if one does not exist. To do this, include the X-ACTIONS header with the value FIND-OR-CREATE-CUSTOMER.

Possible values are:

• CREATE-CUSTOMER

• FIND-OR-CREATE-CUSTOMER

• UPDATE-CUSTOMER

• FIND-PRODUCTS

• USE-FIRST-DESCRIPTION

• USE-FIRST-TOPTEXT-DESCRIPTION

Multiple actions can be combined by separating them with a comma.

Create an invoice

POST https://api5.onfact.be/v1/invoices/:id.json

Path Parameters

Name	Type	Description
id	string	Factuur ID

Headers

Name	Type	Description
X-ACTIONS	string	FIND-OR-CREATE-CUSTOMER
X-SESSION-KEY	string	API Key
X-COMPANY-UUID	string	UUID Van het bedrijf

200

{
    "id": 123,
    "code": "Created"
}